This project focuses on basic cellular transformation events as related to HTLV-I. For this purpose, we study cellular genetic integrity, cell cycle progression and the checkpoints within a cell that guards normal cellular division. Some notable scientific advances from our research program in 2006-2007 include: 1) The discovery of a Tax-binding protein that serves to recruit a de-ubiquitinase that negatively regulates NF-kB signaling; 2) the characterization of the co-operativity between the spindle assembly checkpoint and the p53 checkpoint for tumorigenesis in mice; and 3) the delineation of the requirement of spindle assembly checkpoint protein for the localization of Plk-1 to kinetochores during mitosis and its implication for cellular transformation.